Eley–Rideal and hot-atom dynamics of HD formation by H(D) incident from the gas phase on D(H)-covered Cu(111)

Abstract

We have performed a quasi-classical molecular dynamics study of the reaction dynamics of HD formation by H or D atoms incident from the gas phase on a D or H-covered Cu(111) surface. A key ingredient has been the construction of a model potential-energy surface (PES) that has been exclusively based on results from total energy calculations using the density functional scheme. Our preliminary study supports the Rettner–Auerbach scenario that a significant fraction of the reactions occurs via hot-atom pathways as opposed to Eley–Rideal pathways, in which the incident atom reacts directly with the adsorbed atom. The calculated reaction probabilities and ro-vibrational distributions are in good agreement with the measured distributions. As observed experimentally on other metal surfaces, we also find that the incident atom induces secondary reactions among the adsorbates, producing either H₂ or D₂ molecules. The magnitude and the isotope dependence of the calculated secondary reaction probabilities are in good agreement with measured values.